The present invention relates to an improved pump, particularly for use in the drain outlet of washing machines or the like.
A pump driven by a permanent-magnet synchronous motor is more and more frequently installed in these machines; owing to its characteristics, it certainly achieves the goal of reducing costs and consumption, but it suffers several problems.
In the field of washing machines, manufacturers have developed technical specifications which take into account a wide range of situations, linked in particular to blockages or clogging, or in any case to difficulty in draining.
One of the main problems is linked to the water, which contains detergent foam in an amount which is inversely proportional to the hardness of the water, and to the fact that the user quite often introduces excessive doses of detergent.
The presence of a large amount of foam leads to cavitation of the impeller inside its chamber, with consequent difficulties in draining.
Many technical specifications further require that various types of objects that can be present in the items that are washed must be able to pass through the pump.
For example, socks, sponges of various kinds, metallic coins, hairpins, chains, toothpicks or other objects of this type and size must be able to pass through a drain outlet pump without jamming.
Moreover, lint or threads which are always present in the drain water of a washing machine can coil around the shaft of the motor, blocking it.